Flex + Java crosspolicy send problem

I have a server written in java (also http server). I try to communicate with it from my flex application. It works from FLEX IDE, but not if I run my java server and request the flex application by browser. I receive error: "securityError:. text=Error #2048: Security sandbox violation:".
I found the problem is crosspolicy file. I found also, flex application send to my java server: "policy-file-request".
OK, I receive that request and send back a simple crosspolicy.xml file, actualy i send a string.
It dosen't work....
May be there is another, simpler way?

i have also got the same problem while incorporting Flex with Struts-Hiberbate project.
u add the plugin for iexplorer and firefox.
and add the callback method in the javascript for flex. that callback method should be synchronised with
flex applications
Step:
1.create mxml file in the flex.
2.in mxml file use incorporate with javascript
3.place that mxml file in the java web project.
4.now use script to call.
even if u do not understand feel free to ask me
bye